Help with sub box design - setup and location.

[LINUS]

O.K. - here's what I have so we know what hardware I'm working with.

Headunit - Alpine CDA-9847

Amps:

Eclipse 32430 for mids and tweets (75 x 4)
Eclipse 34230 for sub (370 x 2)

Front mids & tweets : Diamond 5 1/4" and tweets to go in factory locations

Rear deck : got nothing yet - recommendations?

Sub : Kicker L7 (90% positve it's a L7) 4 ohm round DVC. Went on my buddy's recommendaton here - he works in a car stereo shop. All I know is that it's a black cone, not the silver one - don't know if there's any performance differences. Hasn't shown up yet.


I am no expert in car audio, and I prefer tight bass to boomy loose stuff. So with that in mind, what is going to be the best location in the trunk, and with the woofer facing which direction? Sealed or ported box? I've never had a ported box before, and I have liked the sound so far.

I am placing a stress bar in the car, and I am really hoping to use it for an anchor point, unless the woofer should be placed in a drastically different place, like behind the rear driver wheelwell.

I am getting rid of the leather covering on the rear seat, and getting a custom cloth deal done, as well as loosing leather seats and interior panels.

I am very good/excellent at fiberglass, carpentry, and welding so whatever you come up with, I can re-create.

Post up the ideas!

-B

[Mless5]

O.K. - here's what I have so we know what hardware I'm working with.

Headunit - Alpine CDA-9847

Amps:

Eclipse 32430 for mids and tweets (75 x 4)
Eclipse 34230 for sub (370 x 2)

Front mids & tweets : Diamond 5 1/4" and tweets to go in factory locations

Rear deck : got nothing yet - recommendations?

Sub : Kicker L7 (90% positve it's a L7) 4 ohm round DVC. Went on my buddy's recommendaton here - he works in a car stereo shop. All I know is that it's a black cone, not the silver one - don't know if there's any performance differences. Hasn't shown up yet.


I am no expert in car audio, and I prefer tight bass to boomy loose stuff. So with that in mind, what is going to be the best location in the trunk, and with the woofer facing which direction? Sealed or ported box? I've never had a ported box before, and I have liked the sound so far.

I am placing a stress bar in the car, and I am really hoping to use it for an anchor point, unless the woofer should be placed in a drastically different place, like behind the rear driver wheelwell.

I am getting rid of the leather covering on the rear seat, and getting a custom cloth deal done, as well as loosing leather seats and interior panels.

I am very good/excellent at fiberglass, carpentry, and welding so whatever you come up with, I can re-create.

Post up the ideas!

-B

If I was you, I would:

1. Run some cheapo coaxials from the deck if you drive with passengers often. If not, just don't bother.
2. Not sure what that deck is capable of, but if you want to do active (tweeters running from separate amplifier channels), you might need an external electronic crossover that would at least define your midrange, tweeter crossover points/slopes.
3. 4ohm DVC: wire it in for 2 ohms, that way your sub will have more juice (=more cone control). I prefer sealed enclosures: they don't get a s loud, but if you build it right, sq is superb. If you look up the model and specs, there is usually a range of box volume. Going for a smaller volume would generally provide tighter upper end, but less of really low notes (I hate really low, rattly bass). If you have a skipass, kick it out and face the subwoofer towards the interior. Seal off the gap between the box/sub and rear wall.

Igor.

[StereoInstaller1]

Linus, if, in fact, you ordered a DVC 4Ω sub (meaning 2 4Ω coils) to run on your 2 channel amp, return it.

You would have 2 choices: either run it in 8Ω mono (meaning 4Ω per channel) or overheat the shit out of your amp. Neither is good, capiche?

You need to end up at 2Ω per channel, or 4Ω mono. However you do that is immaterial...1 4Ω woofer, 2 8Ω woofers, 4 16Ω woofers...all the same. You can also run 2 4Ω per coil DVC (2Ω total per channel) woofers in stereo...the amp makes the same power. Just make sure you have a 2Ω per channel load.

BTW, Igor, you made several excellent points...except one glaring wrong-ness. Higher loads (lower impedance numerically) makes more voltage. Higher amperage makes for better cone control, higher voltage makes for higher amplitude, lower SQ. Current = cone control.

So, if I had that particular combo, I would find some way to get a true 3 way electronic crosover. You can add one of several choices, there are tons on the market. If you like Alpine decks, get one with "Bass Engine Pro" and you can have all of that crap on your deck in "Pro" mode.

As far as rear speakers go...well, why bother?

BTW, the single most important factor in a "fast" subwoofer is MM, or Moving Mass. Same exact concept as unsprung weight. Lighter mass = quicker acceleration, thus "faster" bass. In a 10" woofer, look for a figure below 135gms if you want truly fast bass. Good luck on that, BTW.

Sealed or ported is decided by the guy who engineered your woofer. Personally, I like the Kicker "Comp" 10 (black cone, yellow stitching) in a 1.0 cu.ft. sealed box...but you said DVC and AFAIK, the Comp is not available DVC.

BTW, since your Eclipse amp makes about 600+WRMS, it will eat that kicker alive. Be careful, use a subsonic filter.

Luke

[LINUS]

Luke -

O.K. - I know nothing involving woofers and the whole point of dual vs. single voice coils, so nothing you say will insult my intellegence here. Just so you know - you can't offend me at all.

My reasoning for the DVC woofer was trunk space. I only want one woofers' volume of lost space back there.

The Eclipse 34230 is kind of a strange amp from what I read. It's really only rated to run 4 ohm stereo from what I get on the tech sheet for it. So what do I do about that? Am I stuck running 2 woofers or ditching the amp?

Here's the link to the amp specs:

http://cartoys.com/cartoy/pdfs/eclipse_amp_manual.pdf

Maybe I'm reading things all wrong.

All I want to do is use my amp to run 1 woofer and get tight, clean bass and not run the amp so hot I cook it. Is this possible?

The reason for rear deck speakers was for rear fill, and the fact that I think the factory location for the front 5 1/4" will end up sounding muddy since my leg is in the way - at least I could put some decent speakers in the rear and maybe bounce the sound off the rear glass to make up for it?

Like I said, I know nothing. If you are laughing right now, please set me straight.

Thanks!

-Ben

[Mless5]

BTW, Igor, you made several excellent points...except one glaring wrong-ness. Higher loads (lower impedance numerically) makes more voltage. Higher amperage makes for better cone control, higher voltage makes for higher amplitude, lower SQ. Current = cone control.

Thanks for correction Luke. I prefer to give my sub its RMS and have some headroom for the amp at the same time.

[StereoInstaller1]

Ben , my goal is not to insult your intellegence, but simply add to your knowledge.

If you lacked intellegence, I would not respond to your post.

So...reading the specs to your amp, I find some anomalies...they list a spec for distorion bridged, but not for power...

Either way, they list 370WRMS per channel, on a 4 ohm load.

You might want to simply run 1 channel per coil, not running the amp in bridged, but stereo. The possibility of channel imbalance does exist, which would tear the voicecoil to shreds.

DVC is ony a method of letting you have more options in wiring, NOT adding anything elso. No better power handling, no better SQ. Exactly the same.

This is a very common myth, BTW.

370 watts X2 is gonna be way more than that sub can deal with...again, be careful.

Go design your box and post specs of what you have in mind. Aim for 1 cubic foot total interior volume.

As far as rear fill, your stock speakers will do just fine, or drop in whatever you feel.

You are correct in thinking the front speaker location blows, BTW. Not so much from your leg blocking it, but from the angle. I just hate having rear speakers, so I don't use them. My solution is speakers that face me...but that is some extreme fabrication to make that happen.

Luke

[LINUS]

Luke -

Thanks for all the help so far - you made a point I fell victim to and that's the whole idea that I could run 2 channels to a DVC woofer. You giving the simple explaination made sense that I would at some point probably shred the voice coil when a conflicting stereo signal was present.

So focusing on the sub amp, what's your advice? Run it in a bridged mode to power a single sub? Risk stereo mode and buy new subs regularly?

As a side note I have BBE, and "bass engine" in the HU, does either qualify as "bass engine pro"?

Sadly, the only reason I am running this HU is for asthetics - it matches my red backlight and it's not painted silver. I don't mind alpine, but I have only ever had Alpine, Eclipse, and Sony HU's - I'll skip the Sony ever again, and I think the new eclipse are too loud looking - or I'm too old.

Seriously, thanks for all the help!
-Ben

[LINUS]

To complicate things further, I just found my old subs I was running with the Eclipse amps.

I have a pair of Boston Acoustic 10.5 LF subs. 4 ohm

Also, I looked at the sub amp and found a little switch with 3 positions:

Mono (L)
Stereo
L + R

I was running it in stereo with the 2 Bostons - can I use one of the modes on the amp to run just one sub without cooking the amp? It would seem the Boston can handle whatever I throw at it:

http://www.bostonacoustics.com/Manuals/ProSpecs.pdf

Even if I blow a sub - who cares? They were paid for long ago. I just don't want to cook the amp.

Advise?

-B

[StereoInstaller1]

YES! Run a single Pro 10 in .8 cu.ft.! Set the subsonic filter to its lowest, set you low pass to 85Hz, set that input switch to L+R, set the gains to your taste.

Pitch the Kicker crap. You own real woofers. Use them. One at a time, baby!

The switch you described has nothing to do with how the amp works. It is simply an "input mode" switch, basically a set of "Y" cords. If you set it to "Mono", only the left input works. L+R is basically 2 "Y" cords, back to back. It "sums" the 2 channels. Stereo is normal of course, but all 3 of these options DO NOT affect how the amp works, just the input stage wiring.

But, as I mentioned in my previous post, your amps spec sheet has some anomalies...such as no power rating for bridged...odd, to say the least.

Due to that switch, we know it will bridge. Power for days!

OK, on to the head unit.

Alpine offers 2 different packages of adjustable crossovers in their decks. You have the basic one, "Bass Engine". Front and rear high pass, plus a subwoofer output.

Bass Engine Pro adds a second setup option: A switch on the bottom of the deck changes the outputs to a true 3 way, being bass, midrange and treble. All 3 outputs have variable crossovers, variable levels.

I have set up tiny little tri-amped (meaning 3 electronic crossover points) systems, using cheap ass junk gear, deck power on stock GM tweeters and mids, and a awalmart amp on a single 12 in a nice ported box on a Bass Engine Pro deck...you should have heard that shit! The best sounding deck powered anything I have ever heard! Simply amazing...so Bass Engine Pro is quite a bit different. If you add real power to that, things really come alive.

BBE is just another name for "Loudness", but with equalization curves designed by Barcus Berry. BFD! Something else to pay licensing for.

Do you yet have a plan for your box design?

Luke

[LINUS]

So my Buddy from the car stereo shop was over tonight - he votes we build a box to use both Bostons - I was supposed to get a CVX Kicker DVC before, but he thinks we can build a box that still gives me some trunk space since the Bostons only need a .5 FT3 volume each.

So now I just need to figure out a good design to make space in the trunk for both subs, both amps, a rear stress bar, and still be able to get to the spare tire.

I have a few working ideas so far, but I plan on a box that will look and perform killer.

I'll PM you Luke when I have some basic measurement, and we'll go from there. Just want to keep things under wraps until I post photos, planning a cool box - just need the time to make it happen.

-B

[808BMW]

If it makes you feel any better about ditching the kicker sub, I'm pretty sure black cones are L5's, and L7's have silver cones. Both are known for their loud bass and muddy sound, opposite of what your going for.